The present invention relates to a tubular cop exchange arrangement for a loom. More particularly, it relates to a tubular cop exchange arrangement for a loom comprising a cop magazine arranged above a web lay and having a cop outlet opening which in a cop exchange position is located closely above an open trough chamber of a shuttle, a cop ejecting device for removing a remaining portion of the cop from the shuttle, a cop pressing device for pressing a new tubular cop from the cop magazine into the trough chamber of the shuttle, a cutting device for separating the weft thread from the ejected remaining portion of the cop and control devices for actuating the above mentioned devices in a respective time sequence.
Tubular cop exchange arrangements of the above mentioned general type are known in the art. One of such arrangements is disclosed, for example, in the German document DE No. 1,535,676. This exchange arrangement is designed for feeding the tubular cop which is completely composed of a cop yarn by a cop pressing device into the trough chamber of a shuttle provided with brush strips or similar holding devices which cooperate with the outer surface of the tubular cop. The ejecting of the remaining portion of the cop from the shuttle is performed by an ejecting arm which is pivotally mounted above the shuttle box. The ejecting arm tears off the remaining portion of the cop which is held in the shuttle end from the trough chamber with its hook-shaped end, and throws the same into a catching basket which is arranged near the loom. In this known structure because of unavoidable tolerances in the outer diameter and in the compressibility and the surface roughness of the used tubular cop, due to its pressing into trough chamber of the shuttle, an exactly reproducible seat is not achieved, and a sufficiently reliable prevention of axial and transverse displacements of the tubular cop in a reciprocating shuttle is not obtained as well. Because of these difficulties, the tubular cop have been used substantially for production of less demanding textile products such as floor cloth, mats or coarse wool covers. For processing synthetic yarn the tubular cops have practically scarcely been used.
The German reference DE No. 1,535,424 discloses a weft coil exchange arrangement for looms in which a weft coil is ejected from the coil magazine by means of a striking hammer with a holding pin in an automatic clamp provided in a web shuttle. Such weft coils are usable only in a limited strength because of weaving requirements, and due to their coil core can carry only relatively small weft thread quantities compared with the tubular cops. Since, especially in full width looms with working width up to 30 m, the weft thread lengths in a shuttle are consumed in a very short time, the exchange points in fabric lie so close to each other that it is required to distribute the points of overlapping of the weft thread ends of the old weft coil and the weft thread starts of the new weft coil over the fabric width. For this purpose, to provide the step identified as a weft application, the loom must be stopped and a part of the introduced weft thread must be pulled out through the upper shed and cut off, and then the filled shuttle must be displaced by approximately 1-2 cm through the upper shed and manually transported into the shuttle box, so that the weft thread ends are placed together with slight overlap. Since this process repeats every 1-2 minutes, a considerable strain on the worker occurs and a significant stoppage time of the loom takes place. The loom can operate only with an efficiency 50-60%.
Because of the great weft thread length of tubular cops, it has been recognized that for producing endlessly woven paper machine fabrics tubular cops have to be used for increasing the running time of the shuttles. However, this has not been implemented since undesirable displacements and premature falling out of the tubular cop in the shuttles which are reciprocable with high speed could not be reliably prevented, and withdrawal of the weft thread from the inner cone of the tubular cop caused uncontrollable balloon formation in the shuttles. Accordingly, it was not possible to achieve a sufficiently reliable automatic exchange of the tubular cop in the shuttles.